Electrical connector with automatic disconnect



May 30, 1967 R. w. BRUSH 3,322,923

ELECTRICAL CONNECTOR -WI'IH AUTOMATIC DISCONNECT Filed se pl. 1964 A Z8 L 32 FIGJ.

INVENTOR RoaEgT- w. BRUSH AT TO RN EYS United States Patent O 3,322,923 ELECTRICAL CONNECTOR WITH AUTOMATIC DISCONNECT Robert W. Brush, Unadilla, N.Y., assignor to The Bendix Corporation, Sidney, N.Y., a corporation of Delaware Filed Sept. 1, 1964, Ser. No. 393,634 23 Claims. (Cl. 200 -142) This invention relates to electrical connectors and more particularly to coupling'means for connectors of the separable plug and socket type.

One of the objects of the invention is to provide novel means for coupling the separable parts of an electrical connector and retaining the same in mated relation.

Another object of the invention is to provide a novelly constructed coupling assembly for separable connector parts whereby the latter may be automatically separated in response to surrounding temperature conditions.

A further object is to provide a novel heat responsive unit adapted to be interposed between separable electrical connector assemblies, whereby the electrical circuits therethrough may be interrupted upon the occurrence of predetermined temperature conditions.

Still another object is to provide novel means for automatically effecting interruption of electrical circuits through an electrical connector without mechanically disconnecting the separable parts thereof.

The above and further objects and novel features of the invention will more fully appear from the following detail description when the same is read in connection with the accompanying drawings. Itis to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

FIG. 1 is an exploded view on an enlarged scale illustrating'the unmated separable parts or assemblies of one form of electrical connector embodying the invention, the receptacle assembly on the left being partially broken away; and the plug assembly on the right being shown in section taken substantially on line 11 of FIG. 3;

FIG. 2 is a detail view illustratin-gtheheat responsive element of the plug assembly of FIG. 1;

FIG. 3 is a detail sectional view on a reduced scale taken on line 3-3 of FIG. 1 showing only the coupling nut; and

FIG. 4 is an axial sectional view illustrating an adaptor embodying the invention for connecting the mateable assemblies of an electrical connector which does'not embody the invention.

One form of the invention is illustrated in FIG. 1, by way of example, as being embodied in a plug and socket type connector comprising male and female parts or assemblies adapted to be detachably coupled together by a bayonet or pin and slot type coupling nut in the manner generally disclosed in Hennessey et al.,' US. Patent No. 2,984,811. The mechanical coupling of the mateable assemblies may, of course, be effected by cooperating screw threads on the coupling nut and one of the connector parts or by other suitable known means, if desired. As shown, one detachable part or assembly 10 generally known as the receptacle comprises a tubular shell 11 within which is mounted an insert 12 of insulating material for supporting one or more contacts, such as pin contact 14. The tubular end portion of shell 11 has a plurality of radially projecting lugs 15 adapted to mate with helical grooves 16 in coupling nut 17 to be more fully hereinafter described.

The male or plug assembly illustrated at the right in FIG. 1 comprises a tubular shell 18 in which an insulat- Patented May 30, 1967 ing insert 19 is mounted for supporting one or more electrical contacts, such as socket contact 20, mateable with pin contact 14. When the plug and receptable assemblies are moved together to mate the contacts 14 and 20 and thereby effect an electrical connection between conductors 21 and 22 connected to the remote ends of the contacts, shell 18 is telescopically received by shell 11 with at least one external rib or key 23 mating with an internal groove 24 to thereby orient the assemblies and retain them against relative angular movement.

Novel coupling means are contemplated by the invention for drawing the plug and receptacle assemblies into mated relation and for maintaining the same in mated relation while permitting automatic separation thereof in response to predetermined relatively high tempenatures. In the form shown in FIG. 1, said coupling means is constituted by an assembly comprising the tubular body or coupling nut 17, a plurality of coil springs 25 housed in recesses 26, a temperature responsive element in the form of a split ring 27 engaging an internal groove 28 in nut 17, and an annular spacer or force transmitting member 29. The coupling assembly may also comprise a split annular wavy leaf spring 30 and a split retaining ring or stop 31 in an internal groove 32 in nut 17.

The novel coupling assembly above described surrounds shell 18 for rotation and limited axial movement relative thereto, the axial movement being limited by an external flange 33 on the shell and a retaining ring or collar 34 threaded onto the end of shell 18. Flange 33 and the end of ring 34 which may be regarded as part of shell 18 define an external groove into which an inner portion 35 of member 29 extends and is captured with spring 30 to thereby limit the normal relative axial movement between the coupling nut assembly and shell 18, 34. Another portion of member 29 is preferably piloted on collar 34 and is thereby guided for axial movement thereon. The outer peripheral portion of ring member 29 extends radially between the heat responsive stop 27 and the free ends of springs 25 which are under compression. The outer periphery of member 29 closely approaches the inner surface of nut 17 and is preferably slightly tapered inwardly from the surface thereof which shells 11 and 18 after the inserts 12 and 19 have been drawn into abutting engagement by rotation of nut 17 'while lugs 15 and grooves 16 are engaged. Thus, during the final rotation of nut 17, the coupling nutassembly moves axially to the left relative to shell 18, thereby compressing spring 30 as portion 35 of member 29 moves axially away from the end of retaining ring 34. When cooperable screw threads are provided on nut 17 and shell 11, the part 35 of ring 29 may have a relatively close fit between flange 33 and collar 34 without the need for spring 30.v

Heat responsive split ring 27 constitutes a stop which normally limits the axial movement of annular member 29 and hence, of shell 18, 34.toward the right (FIG. 1) relative to tubular body or nut 17 and is made of a composition which is capable of withstanding the force exerted by springs 25, aided somewhat by spring 30, under normal temperature conditions, but which will soften and yield to said forces at an elevated temperature. One. material which has been found to be particularly suitable is a plastic composition sol-d un derthe trade name Delrin. This material has the property of losing its shear strength within a short temperature range beginning at about 350 F. The temperature at which member 27 will yield and be sheared 01f in line with the outer edge of member 29 may be regulated somewhat by varying the spring pressure applied, varying the thickness of member 27, or varying the area to be sheared, such as by varying the extent and number of teeth 36 on the outer periphery of member 27 which extend into groove 28.

It will thus be seen that when the assemble-d connector and hence, heat responsive ring 27, are subjected to a predetermined elevated temperature, said ring will be sheared adjacent the inner surface of nut 17 at the roots operable pin and socket contacts mounted in said shells,

of teeth 36 by the force of the springs transmitted through annular member 29. In the illustrated embodiment, the ring portion 35 will be spaced to the left from the inner end of collar 34 with spring 30 under compression so that the entire force of the springs and are acting to shear ring 27 until the flange reengages the end of collar 34, whereupon the entire plug assembly 13 is moved by springs 25 toward the right relative to nut 17 and receptacle assembly 10 to thereby disengage contacts 14 and 20.

If desired, this automatic disengagement movement in response to elevate-d temperature may be limited by stop ring 31 or equivalent means engageable by the sheared portion of ring 27 or by the outer peripheral portion of ring 29 if the former should fall out or collapse. Thus, the plug, receptacle and coupling assemblies will remain mechanically connected after the electrical connection 14, 20 has been interrupted. To assist in avoidance of any tilting and hence, binding of the receptacle assembly relative to the coupling nut or shell 11 after ring 27 has been sheared, a cylindrical extension 37 may be provided as an integral part of retaining collar 34 to slide in stop ring 31 and thus function as a guide.

In order that the invention may be made readily available for installations already in the field, it may be incorporated in an adaptor which may be sandwiched between a normal plug and receptacle. One form of such an adaptor is illustrated in FIG. 4, wherein the same reference numerals are used to indicate parts which are like or comparable to parts identified with the same numerals in FIG. 1. The contact 40 has a socket 41 at one end and a pin 42 at the other end while the adaptor shell 43 has an extension 44 comparable to the corresponding parts of receptacle assembly 13.

Thus, the left hand end of the adaptor of FIG. 3 may be mated with and coupled to the receptacle 10 of FIG. 1 in the same manner as plug assembly 13 is coupled therewith. The right hand end of the adaptor is comparable to receptacle assembly 10 and may be mated with and coupled to a plug and coupling nut assembly which does not necessarily embody the features of the invention, such as one illustrated in the above-mentioned US. Patent No. 2,984,811. When ring 27 (FIG. 4) yields and is sheared at a predetermined temperature, the central portion 40-44 of the adaptor will be moved to the right with the plug assembly coupled therewith until ring 29 engages stop 31. This movement of the parts will disengage socket 41 from pin 14 and interrupt the electrical circuit.

Although only a limited number of embodiments of the invention have been illustrated in the drawing and described in the foregoing specification, it is to be expressly understood that the invention is not limited thereto. If desired, for example, the heat responsive element 27 may be mounted on ring 29 and engage an internal shoulder in nut .or body 17, the pin contact 14 may be mounted in the plug assembly 13, and socket contact 20 may be incorporated in the receptacle assembly 10. Various other changes may also be made, such as in the specific design and arrangement of the parts illustrated and the materials suggested, without departing from the spirit and scope of the invention, as will now be apparent to those skilled in the art.

and coupling means cooperable with said shells locking the same together with said contacts in mating relationship, said coupling means comprising a nut detachably connected with one of said shells, an annular member rotatable relative to said nut and mounted on the other of said shells for axial movement therewith and heatresponsive means for normally limiting relative axial movement of said member and nut in one direction and for automatically releasing said other shell and member for axial movement relative to said nut and said one shell in said one direction to disengage said contacts.

2. An electrical connector as defined in claim 1, wherein said heat-responsive means comprises heat softenable retaining means.

3. An electrical connector as defined in claim 1 comprising means for imparting contact-disengaging move ment to one of said shells upon release thereof by said heat-responsive means.

4. An electrical connector .as defined in claim 1 comprising resilient means carried by said coupling means for imparting contact-disengaging movement to one of said shells upon release thereof by said heat-responsive means.

5. An electrical connector comprising two tubular shells, an insulating insert in each shell, matable pin and socket contacts mounted in said inserts, and coupling means cooperable with said shells for drawing the shells toward each other and detachably locking the same together with said contacts in mating relation, said coupling means comprising a nut detachably connected to one of said shells and temperature-responsive means mounted on and rotatable with said nut for automatically release ing one of said shells to permit axial separation thereof from the other shell to disengage said contacts.

6. A coupling assembly releasably locking two electrical connector parts in mating relation comprising a tubular body member detachably connectable with one of said parts, an annular member slidable axially in said body member rotatable relative to and adapted for interlocking relation with the other of said connector parts for axial movement therewith, force-applying means interposed between said members, and stop means mounted on one of said members and engageable by the other of said members for limiting relative axial movement of said members by said force-applying means while permitting relative rotation of said members, said stop means being ineffective to resist the force of said force-applying means under predetermined operating conditions.

7. A coupling assembly as defined in claim 6, wherein said stop means comprises an element of heat-softenable material.

8. A coupling assembly as defined in claim 6, wherein said stop means comprises an element shearable by the force of said force-applying means under said predetermined operating conditions.

9. A coupling assembly as defined in claim 6, wherein said force-applying means exerts a constant pre-determined force and said stop means becomes ineifective to resist said force when heated to a sufficiently high temperature.

10. An electrical connector comprising two shells, an insulating insert in each shell, matable pin and socket contacts mounted in said inserts, a coupling nut assembly cooperable with said shells for drawing the shells together upon rotation of the coupling means relative to the shells and locking the same together with said contacts in mating relation, said assembly comprising a tubular body member cooperable with one of said shells, an annular member slidable axially in said body member and having interlocking relation with the other of said shells for axial movement therewith, force-applying means interposed between the said members, and stop means for limiting axial movement of saidother shell and annular member relative to said body member in contact disengaging direction by said force-applying means, said stop means being ineffective to resist the force of said force-applying means under predetermined conditions.

11. An electrical connector as definedin claim comprising resilient means interposed between said annular member and said other shell, said resilient means being compressible upon axial movement of said annular member relative to said other shell by axial movement of said body member relative to the shells after the latter have been drawn together. i

12. In an electrical connector, the combination comprising a tubular shell, an insulating insert in said shell, a contact supported by said insert and a coupling nut assembly mounted on said shell for rotation relative thereto and axial movement therewith, said assembly comprising a tubular body surrounding said shell, an annular member surrounding said shell within said body, said shell comprising means for limiting axial movement of said annular member relative to the shell ineither direction, stop means mounted on and projecting inwardly from the inner surface of said body for normally limiting axial movement of said annular member relative to said body in one direction, and energy storage means for urging movement of said member relative to said body in said one direction and for rendering said stop means ineffective under predetermined operating conditions.

13. The combination defined in claim 12, wherein said shell comprises a first part having an external abutment and a second part removably mounted on said first part, said abutment and said' second part constituting said means for limiting axial movement of said member relative to said shell.

14. The combination defined in claim 12, wherein said stop means is heat-softenable and shearable by the force of said energy storage means under predetermined temperature conditions;

15. The combination defined in claim 12 comprising a second stop means on said body for limiting axial movement of said member and shell relative to said body when said first-named stop means is rendered ineffective.

16. The combination as defined in claim 15, wherein said second stop means is an internal annular flange in said body and further comprising a piston-like guide carried by said'shell and having a sliding fitin said annular flange.

17. The combination defined in claim 12 comprising resilient means-interposed between said annular member and shell for yieldably resisting relative axial movement of said shell and member.

18. The combination as defined in claim 17, wherein said resilient means comprises a wavy annular spring.

19. The combination defined in claim 12, wherein said stop means comprises a split ring of plastic material mounted in a groove within said tubular body and rendered readily shearable upon application of heat.

20. The combination as defined in claim 19, wherein said split ring has an interrupted or toothed periphery which projects into said groove.

21. An electrical connector comprising a tubular shell and a coupling nut assembly mounted on said shell for rotation relative thereto and limited axial movement relative thereto, said assembly comprising a tubular body surrounding said shell, an annular member surrounding said shell within said body, said shell comprising means limiting axial movement of said annular member relative to said shell in either direction, means 'operatively interposed between said body and member normally limiting axial movement of said member relative to said body in one direction, and force-applying means for imparting axial movement to one of said body and member relative to the other for shearing said last-named means to thereby release said shell for axial movement relative to said body in said one direction.

22. An electrical connector as defined in claim 21, wherein said force-applying means comprises resilient means under compression.

23. An electrical connector as defined in claim 22, wherein said resilient means are interposed between said body and member to urge the latter against said means limiting axial movement of said member relative to the body in said one direction.

References Cited 'UNITED STATES PATENTS Kokalas 339-45 BERNARD A. GILHEANY, Primary Examiner. H. B. GILSON, Assistant Examiner. 

1. AN ELECTRICAL CONNECTOR COMPRISING TWO SHELLS, COOPERABLE PIN AND SOCKET CONTACT MOUNTED IN SAID SHELLS, AND COUPLING MEANS COOPERABLE WITH SAID SHELLS LOCKING THE SAME TOGEHTER WITH SAID CONTACTS IN MATING RELATIONSHIP, SAID COUPLING MEANS COMPRISING A NUT DETACHABLY CONNECTED WITH ONE OF SAID SHELLS, AN ANNULAR MEMBER ROTATABLE RELATIVE TO SAID NUT AND MOUNTED ON THE OTHER OF SAID SHELLS FOR AXIAL MOVEMENT THEREWITH AND HEAT- 